For a wide variety of reasons, it is often necessary to transplant live trees. This is a delicate process requiring the tree to be excavated with the roots substantially intact and maintained in a large quantity or ball of earth so that the roots and associated dirt may be placed within a hole at another location. While such a process may be accomplished by hand when small trees are involved, transplanting larger trees requires specialized equipment.
Mechanized tree transplanting machines capable of excavating large trees and transporting the same to another location are known and commercially available. Typically, such devices include a plurality of blades that may be pushed into the ground around a tree by hydraulic cylinders. Once fully inserted into the ground, a lifting mechanism such as another hydraulic cylinder is employed to lift the tree, and any earth surrounding the roots, out of the ground. Such devices are ordinarily mounted on a trailer or other wheeled vehicle, allowing the tree to be easily transported to the new location where it is lowered into a hole that has been previously excavated to receive the tree.
While the use of such hydraulically powered tree spades has proven to be generally successful, in many instances, the hydraulic cylinders are unable to effectively force the excavation blades into the ground surrounding the tree. This is often due to an abundance of tough roots, rocks, or merely particularly hard soil. Attempting to force the excavation blades into the ground under such conditions may overload the hydraulic cylinders, hoses, pumps, and other components resulting in damage to the hydraulic system and usually in spilled hydraulic fluid. While it is possible to increase the capacity of the hydraulic cylinders used to force the excavation blades into the ground, these larger hydraulic cylinders are more expensive and may require other machine components to be correspondingly strengthened which increases the cost of the machine. Merely increasing the size of the hydraulic cylinders without changing the action or design of the overall machine may result in damage to the excavating blades and or related components. Because the constant pushing or pulling force of ordinary fluid cylinders is often not sufficient to force the excavation blades through roots, rocks, and other obstructions, when one or more of the excavating blades is blocked by such an obstruction, the reaction force of the hydraulic cylinder(s) against the obstruction often causes the tree spade to be suddenly lifted off the ground. This is a dangerous condition for the machine operator and can also result in damage to the tree spade or the tree being removed from the ground.
Another prior device is a small, lightweight, hand-operated device that utilizes a rapidly reciprocating hammer to individually force a plurality of blades into the ground surrounding a tree. Once the tree is completely encircled by these separate blades, the apparatus is moved out of position leaving the blades behind. The blades are tied together at the upper regions by spoke-like members so that a separate machine, such as a tractor, may be moved into position to lift the tree from the ground. The apparatus is sufficiently lightweight that it may be lifted into position by two workers. However, the extremely lightweight nature of the apparatus requires a worker to stand upon the machine and grasp the hammer apparatus to provide the weight necessary to force the blades into the ground. This results in a large amount of operator fatigue and necessarily limits the effectiveness of the apparatus when extremely thick roots or rocks are found around the base of a tree. Also, such a prior device does not include a source of power to drive the rapidly reciprocating hammer and therefore, an external source such as a portable air compressor must be provided nearby the apparatus to supply power to the hammer.
In light of the foregoing, there has been found a need to provide a tree transplanting apparatus capable of driving tree excavating blades into the ground around a tree even when extremely hard soil, roots, rocks, or other obstructions are found around the tree being transplanted. There has also been found a need to provide such an apparatus that does not require a large amount of exertion on the pan of the machine operator and that includes a source of power so that the apparatus need not be connected to an external source.